It's nowhere near time to change out the tires that came with my bike, but nevertheless, I'm curious, and had a few questions.

Currently I ride on 700x25c tires, front and rear. They're working out fine; no real need to change.

But is there a difference that a mere mortal can distinguish between riding on 25's and 23's? I know that in theory the 23's are going to be lighter, less forgiving of road irregularities, and quicker to accelerate (all else being equal).

Also, I've heard of people using a 25 in the rear and a 23 in front. It would seem to me that whatever minor advantage is gained by going with 23 front and rear would be greatly diminished by only putting the narrower tire in the front. But I'm interested in hearing peoples' experience here too.

Finally, how does one make sense out of all the rubber densities and thread counts out there?

Go with 23's, front AND back.
They roll faster than 25's.
Do it today!

Slackerprince

My Roubaix came with 25's on 'em. I switched them out for 23's to let me get my front wheel past my brake caliper without deflating it, and also to pickup less road junk (the specialized tires were very sticky). Love my 23's (Pro3Races).

question do 25's handle better than 23's? or is the performance handling wise the exact same. I would think wider tires would help when takin sharp hard turns and that wider tires would have more surface area which woul keep your back tire form sliding out form under you when takin hard turns at high speeds. thanks

I think with the kind of pressures the tires are run at (over 100psi) it doesn't make much difference. Check out sheldon's site about cornering, where he describes tires, tire treads, widths, wet and dry cornering etc.

There have been many threads on here over the years where somebody actually measures various 25c and 23c tires and discovers that not all 25c's are wider then all 23c's.